MainActivity.kt

package com.example.todoapp

import android.app.AlarmManager
import android.app.Notification
import android.app.PendingIntent
import android.content.Context
import android.content.Context.ALARM_SERVICE
import android.content.Intent
import android.graphics.*
import android.os.Bundle
import android.os.SystemClock
import android.view.Menu
import android.view.MenuItem
import android.view.View
import androidx.appcompat.app.AppCompatActivity
import androidx.appcompat.widget.SearchView
import androidx.core.app.NotificationCompat
import androidx.core.content.ContextCompat.getSystemService
import androidx.lifecycle.Observer
import androidx.recyclerview.widget.ItemTouchHelper
import androidx.recyclerview.widget.LinearLayoutManager
import androidx.recyclerview.widget.RecyclerView
import kotlinx.android.synthetic.main.activity_main.*
import kotlinx.coroutines.Dispatchers
import kotlinx.coroutines.GlobalScope
import kotlinx.coroutines.launch

class MainActivity : AppCompatActivity() {

    val list = arrayListOf<TodoModel>()
    var adapter = TodoAdapter(list)
    val db by lazy {
        AppDatabase.getDatabase(this)
    }

    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(R.layout.activity_main)
        setSupportActionBar(toolbar)
        todoRv.apply {
            layoutManager = LinearLayoutManager(this@MainActivity)
            adapter = this@MainActivity.adapter
        }

        initSwipe()

        db.todoDao().getTask().observe(this, Observer {
            if (!it.isNullOrEmpty()) {
                list.clear()
                list.addAll(it)
                adapter.notifyDataSetChanged()
            }else{
                list.clear()
                adapter.notifyDataSetChanged()
            }
        })



    }

    fun initSwipe() {
        val simpleItemTouchCallback = object : ItemTouchHelper.SimpleCallback(
            0,
            ItemTouchHelper.LEFT or ItemTouchHelper.RIGHT
        ) {
            override fun onMove(
                recyclerView: RecyclerView,
                viewHolder: RecyclerView.ViewHolder,
                target: RecyclerView.ViewHolder
            ): Boolean = false

            override fun onSwiped(viewHolder: RecyclerView.ViewHolder, direction: Int) {
                val position = viewHolder.adapterPosition

                if (direction == ItemTouchHelper.LEFT) {
                    GlobalScope.launch(Dispatchers.IO) {
                        db.todoDao().deleteTask(adapter.getItemId(position))
                    }
                } else if (direction == ItemTouchHelper.RIGHT) {
                    GlobalScope.launch(Dispatchers.IO) {
                        db.todoDao().finishTask(adapter.getItemId(position))
                    }
                }
            }

            override fun onChildDraw(
                canvas: Canvas,
                recyclerView: RecyclerView,
                viewHolder: RecyclerView.ViewHolder,
                dX: Float,
                dY: Float,
                actionState: Int,
                isCurrentlyActive: Boolean
            ) {
                if (actionState == ItemTouchHelper.ACTION_STATE_SWIPE) {
                    val itemView = viewHolder.itemView

                    val paint = Paint()
                    val icon: Bitmap

                    if (dX > 0) {

                        icon = BitmapFactory.decodeResource(resources, R.mipmap.ic_check_white_png)

                        paint.color = Color.parseColor("#388E3C")

                        canvas.drawRect(
                            itemView.left.toFloat(), itemView.top.toFloat(),
                            itemView.left.toFloat() + dX, itemView.bottom.toFloat(), paint
                        )

                        canvas.drawBitmap(
                            icon,
                            itemView.left.toFloat(),
                            itemView.top.toFloat() + (itemView.bottom.toFloat() - itemView.top.toFloat() - icon.height.toFloat()) / 2,
                            paint
                        )


                    } else {
                        icon = BitmapFactory.decodeResource(resources, R.mipmap.ic_delete_white_png)

                        paint.color = Color.parseColor("#D32F2F")

                        canvas.drawRect(
                            itemView.right.toFloat() + dX, itemView.top.toFloat(),
                            itemView.right.toFloat(), itemView.bottom.toFloat(), paint
                        )

                        canvas.drawBitmap(
                            icon,
                            itemView.right.toFloat() - icon.width,
                            itemView.top.toFloat() + (itemView.bottom.toFloat() - itemView.top.toFloat() - icon.height.toFloat()) / 2,
                            paint
                        )
                    }
                    viewHolder.itemView.translationX = dX


                } else {
                    super.onChildDraw(
                        canvas,
                        recyclerView,
                        viewHolder,
                        dX,
                        dY,
                        actionState,
                        isCurrentlyActive
                    )
                }
            }


        }

        val itemTouchHelper = ItemTouchHelper(simpleItemTouchCallback)
        itemTouchHelper.attachToRecyclerView(todoRv)
    }

    override fun onCreateOptionsMenu(menu: Menu): Boolean {
        menuInflater.inflate(R.menu.main_menu, menu)
        val item = menu.findItem(R.id.search)
        val searchView = item.actionView as SearchView
        item.setOnActionExpandListener(object :MenuItem.OnActionExpandListener{
            override fun onMenuItemActionExpand(item: MenuItem?): Boolean {
                displayTodo()
                return true
            }

            override fun onMenuItemActionCollapse(item: MenuItem?): Boolean {
                displayTodo()
                return true
            }

        })
        searchView.setOnQueryTextListener(object : SearchView.OnQueryTextListener{
            override fun onQueryTextSubmit(query: String?): Boolean {
                return false
            }

            override fun onQueryTextChange(newText: String?): Boolean {
                if(!newText.isNullOrEmpty()){
                    displayTodo(newText)
                }
                return true
            }

        })

        return super.onCreateOptionsMenu(menu)
    }

    fun displayTodo(newText: String = "") {
        db.todoDao().getTask().observe(this, Observer {
            if(it.isNotEmpty()){
                list.clear()
                list.addAll(
                    it.filter { todo ->
                        todo.title.contains(newText,true)
                    }
                )
                adapter.notifyDataSetChanged()
            }
        })
    }

    override fun onOptionsItemSelected(item: MenuItem): Boolean {
        when (item.itemId) {
            R.id.history -> {
                startActivity(Intent(this, HistoryActivity::class.java))
            }
        }
        return super.onOptionsItemSelected(item)
    }

    fun openNewTask(view: View) {
        startActivity(Intent(this, TaskActivity::class.java))
    }

}